However hour-long delays are still being experienced on the North Shore Line and flow-on delays of up to 30 minutes across the entire CityRail network after the overhead wiring problem at Waverton early on Monday morning.

A Transport Management Centre spokesman said the problem at Waverton had been fixed just after 10.30am, and delays were expected to ease in the coming hours.

Commuters faced long bus queues in the Sydney CBD today after North Shore Line trains were disrupted. Photo: Matthew Huckstepp

Mr Slezak said replacement buses had been arriving, but they had been delayed by peak-hour traffic and struggled to move the volumes of commuters displaced from trains.

"They hardly make a dent," he said, estimating he would face another one- to two-hour wait to get to work at Chatswood.

At 10am on Monday, hundreds of people were queued outside North Sydney railway station to catch replacement bus services.

‘‘It was mental. It looks like it has calmed down a little bit compared to what it was earlier this morning, but there are still lots of people,’’ said a worker in a business near the station.

Commuters vented their frustration on social media, including one woman who tweeted that the queue at North Sydney ran around a corner and then doubled back. SHe caught a taxi to work with her colleagues, who were also caught up in bus queues.

Another commuter said her boss drove to North Sydney station to pick her up.

Just after 10.30am, the Transport Management Centre said the problem at Waverton had been fixed.

‘‘There are train delays on the North Shore Line of up to 60 minutes, while there are also flow-on delays across the CityRail network of up to 30 minutes,’’ the spokesman said.

‘‘Delays will begin to ease now that repairs at Waverton have been completed.’’

He said passengers could use their train tickets for travel on STA Sydney Buses and Sydney Ferries on Monday morning due to the disruption.

A NSW Police spokeswoman said officers were called to set up barriers near Wynyard station as a safety precaution to keep people from spilling on to the road.